This invention relates to a push button-actuated overload protective circuit breaker with bimetal cutout, and more particularly to such a circuit breaker having a housing, a push button extending into the housing from the outside, and, in the interior of the housing,
(a) a fixed contact element and a bimetal contact element, arranged besides each other and being devised each as an alongated punched-out part having the shape of substantially a right parallelepiped of flat rectangular cross-sectional area, both contact elements being mounted in a mounting wall of the housing, and having each a longitudinal central axis and two opposite large faces and, connecting them, two opposite narrow side faces therebetween, main sections through the longitudinal axes parallel with the large faces being located in planes which are spaced from, but parallel with each other, and each of the contact elements having an inner free end, located inside the housing interior; and a fixed contact post mounted on the free end of the fixed contact element,
(b) a bimetal snap disc being fastened with a first end thereof on the inner free end of the bimetal contact element and extending transverse to the longitudinal axes of the contact elements, another end of the bimetal snap disc, opposite said first end thereof, overlapping the inner free end of the fixed contact element; and a movable contact post on the said other end of the bimetal snap disc;
said contact post on the bimetal contact element abutting said contact post on the fixed contact element with bias when the bimetal contact element and bimetal snap disc thereon are in unheated rest position,
(c) an insulating wall member having a wall surface extending between the main sections of the two contact elements and being supported for displacement in the direction of the longitudinal axis of the circuit breaker; which insulating wall member is in a position outside but adjacent the two contact posts when they abut against one another in the rest position; and which insulating wall member can be moved into a separating position between the two contact posts when the latter are moved apart from each other due to bending of the bimetal snap disc relative to a fixed portion of the bimetal contact element; and which insulating wall member is adapted for being displaced from a contact posts-separating position to the rest position by means of the aforesaid pressure button.
A circuit breaker of this kind has been described in U.S. Pat. No. 4,573,031 issued to Fritz Krasser on Feb. 25, 1986, which patent corresponds to German Offenlegungsschrift No. DE 33 42 144 published on May 30, 1985.
This known overload protective circuit breaker is satisfactory in most respects, but time required for cooling the circuit breaker is relatively long, and the interruption of the electric arc when breaking circuit is sometimes not as sharp as desired.